【作者】 周贤杰；

【导师】 罗固源；

【作者基本信息】 重庆大学 ， 环境工程， 2008， 博士

【摘要】 三峡库区蓄水后,由于水文条件发生明显改变,次级河流出现大面积富营养化现象,其显著特征就是藻类疯长引起水体Chla含量增加(在严重的累积区Chla浓度高达数百毫克/立方米)而透明度、溶解氧降低。水体富营养化不仅造成水环境功能障碍,影响养殖和景观旅游,其产生的藻毒素及衍生物对人体健康和生存、繁衍存在着严重危害。此现象已经引起国家有关部门的高度重视。然而富营养化研究历史短,且其发生、发展与控制复杂,到目前,世界各国表征水体富营养化的指标体系、评价标准和评价方法等都没有统一。为了维护库区的水环境安全,本文跟踪监测10条典型次级河流水质并对其现状做出评价,建立起相应的富营养化经验模型;分析藻类生长过程的生化机制及影响因素,提出藻细胞活体分析和测定方法,并开展次级河流藻类生长的试验研究。下面简要介绍了本文研究的主要内容和取得的成果。①库区10条典型次级河流富营养化现状研究结果表明:2004年至2006年,次级河流都发生了不同程度的富营养化现象,优势藻通常为硅藻、甲藻、蓝藻和绿藻,有时也可能是隐藻或其它藻。②库区次级河流富营养化经验模型验证结果表明:当把Chla预测值与实测值相对误差的绝对值小于70%的模型作为合格模型进行统计时,在有显著性意义(α=0.10)的57个模型中,Chla-TP模型、Chla-CODMn模型、Chla-TN模型和Chla-SD模型的合格率分别为77%、73%、68%和65%。③库区次级河流藻类生长机制分析结果表明:适宜的温度和充足的光照,充足的氮磷营养盐,缓流的流态是藻类大量生长的最必要条件。④库区大宁河水样藻类生长试验结果表明:1) Chla藻细胞活体分析法测定值(x)在0~27 mg/m3范围内与丙酮萃取分光光度法测定值(y)成正比,其一元线性回归方程为y=4.15x+2.48(mg/m3),R2=0.9985,t检验方程高度显著(α=0.01)。2)当控制水样温度为20℃、光照为8000Lx、DIN和PO4-P浓度分别为85.71μmol/L、2.86μmol/L时,藻类生长最好;磷为该水域藻类生长的限制性营养元素,藻类生长氮磷元素适宜摩尔比约为30:1。在适宜生长条件下,对数期藻细胞比生长率达到1.03/d,稳定期Chla最大浓度达到110mg/m3。3)在温度为20℃、光照为8000Lx、氮磷摩尔比为30:1的环境条件下,藻类最大生长率μmax=1.16/d;氮磷营养盐半饱和浓度KDIN=8.65μmol/L,KPO4-P=0.29μmol/L。更多还原

【Abstract】 Eutrophication phenomenon has appeared large-proportion in tributaries to the Three Gorges Reservoir after impoundment because its hydrodynamics condition has been changed obviously. The obvious characters are Chlorophyll-a(Chla) concentration increased (The Chla concentration even reach hundreds milligramme per stere in serious area), transparence and dissolving oxygen reduced. Not only it can lead to water function obstacle, affect breed aquatics and sightseeing, but also the algae toxin and derivative it procreant are seriously harmful to health,survival and multiplication of people. This phenomenon has aroused highly attention of the departments. But the history of eutrophication investigation is short, and its occurrence, development and control are complex. Thus, till now, there are no unified standards of index system, appraise criterion and method which evaluate the water eutrophication in the world. In order to guarantee safety of water environment in the Three Gorges Reservoir, water quality actualities of 10 typical tributaries were monitored and appraised, and the experiential eutrophication models were founded in this thesis. Algae growth mechanism and its effect factors were analyzed, active algae cell analytical method and mensuration were brought forward, and trial studies of algae growth in tributaries were carried. The contents and results were summarized as below.①Eutrophication of 10 tributaries to the Three Gorges Reservoir was studied. It showed that different degrees of eutrophication were occurred in 10 tributaries from 2004 to 2006.The dominance algae were Bacillariophyta, Pyrrophyta, Cyanophyta and Chlorophyta, but sometimes were Cryptophyta and others.②The experiential model of eutrophication of the tributaries to the Three Gorges Reservoir was validated. It showed that the eligibility ration of Chla-TP model, Chla-CODMn model, Chla-TN model and Chla-SD model would be 77%, 75%,68% and 67% respectively in 57 models which has remarkable meaning(α=0.10), if taking absolute value of RE% of Chla forecast value and monitoring value less than 80% as eligible date.③Algae growth mechanism of the tributaries in the Three Gorges Reservoir was analyzed. It showed that the necessary conditions of eutrophication were appropriate temperature and abundance illumination, abundance nitrogen and phosphorus nutrients, slow flow velocity. ④Algae growth experiments of Daning River in the Three Gorges Reservoir were carried. Results showed that:1) In 0~27mg/m3, the concentration of Chla measured by active algae cell analytical method(x) is directly proportional to the value measured by acetone extraction spectrophotometry(y). The regression equation was y=4.15x+2.48 (mg/m3), R2=0.9985. T-test showed that the equation has remarkable meaning (α=0.01).2) The optimal condition for algal growth was that the water temperature and illumination were 20℃and 8000Lx, the concentrations of DIN and PO4-P were 85.71μmol/L and 2.86μmol/L respectively. Phosphorus was the limiting nutrition element for algal growth, and the optimal ratio of nitrogen to phosphorus was 30:1. Under the optimal condition, the specific growth rate was 1.03/d at the expotential phase, and the maximum Chla concentration was 110 mg/L at the stationary phase.3) Under the conditions of that the water temperature and illumination were 20℃and 8000Lx respectively, and the ratio of phosphorus and nitrogen concentrations was 30:1, the maximum growth rate were 1.16/ d both nitrogen and phosphorus, and the half-saturated constants of nitrogen-limit and phosphorus-limit were 8.65μmol/L and 0.29μmol/L respectively.更多还原